Role of arginine kinase in Paramecium tetraurelia (Ciliophora, Peniculida): subcellular localization of AK3 and phosphoarginine shuttle system in cilia

•The PMF analysis indicated that the C-terminal peptide of AK3 is farnesylated, suggesting that the AK3 is likely to be bound to membrane.•AK3 was detected in the ciliary fraction by Western blot analysis.•The feeding RNA interference experiment indicated that the ciliary movement of AK1- and AK3-silenced cells was significantly reduced to half the value of control cells.•P. tetraurelia AK3 affects swimming velocity, presumably through the phosphoarginine shuttle system present in cilia.